Automatic telephone-exchange system



June 30, 1925. 1,543,937

J. L. MCQUARRIE AUTOMATIC TELEPHONE EXCHANGE SYSTEM Filed Nov. 28, 1921Awe/fian- James 1. M al/(rifle.

and a secondary line switch.

Patented June 30, i925 1 UNITED STATES PATENT OFFICE.

JAMES L. TJIGQUARBIE, 0F NEVJ YORK, N. Y., ASSIGNOR- TO WESTERN ELECTRICCOM- PANY, INCORPORATED, OF NEW YORK, H. Y., A COR-POEATION OF NEW YORK.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEIVI.

Application filed November 28, 1921. Serial No. 518,326.

T 0 all whom it may concern:

Be it known that I, Jeans L. LICQUARRIE, a citizen of the United Statesof America,

residing at New York, in the county of New 5 York, State of New York,have invented certain new and useful Improvements in AutomaticTelephone-Exchange Systems, of

which the following is afull, clear, concise,

line to an idle one of a large number of common trunks by means simplein construction, positive and speedy in action,

which permits of very efficient trunking, and in which first cost andmaintenance charges shall below.

In accordance with this invention a unitary switching structure isprovided having extensions of each incoming line located in proximity tolink conductors, these latter conductors being located in proximity totrunk conductors, means being provided within said unitarv switchingstructure for connecting an incoming set of, line conductors on which acall has arrived instantaneously to an idle trunk through theintermediation of a set of link conductors, an idle set of trunk andlink conductors being preselected in readiness to extend the call bysuitable mechanism.

In machine switching telephone exchange systems it has been found thatby making all the first selectors accessible to all the subscriberslines, more efficient trunking is obtained than by making groups offirst selectors individual to groups of subscribers lines.

Various schemes have been devised to accomplish this purpose, one of thewell-known arrangements providing primary and secondary line switcheswhereby any subscribers line can be connected to an idle one of all ofthe first selectors by the successive operations of a primary lineswitch This arrangement and others heretofore known to me req iresenarates r ctures for aocomplis'lr ing the primary and secondarytrunking functions.

The invention contemplates providing a simple unitary switchingstructure to accomplish both primary and secondary switching operations.I

In the present embodiment of the invention, a connection between asubscribers line, upon which a call has been initiated, and one of thecommon outgoing trunks is instantaneously effected by intersectingmovable bars which cooperate under the control of suitable magnets tobring contact sets or extensions of the calling subscribers line andcontact sets or extensions of an idle trunk into contact with contactsets of an idle link or transfer circuit, the trunk and link used beingpredetermined by allotters.

More specifically a single unitary switching structure is provided inwhich conductors forming extensions of the subscribers lines of a givengroup intersect or .7 cross conductors forming link or transfercircuits, these link conductors being indi-. vidual to this group oflines. The conductors forming the link circuits individual to a numberof groups of subscribers" lines in turn intersect conductors of all thetrunks or outgoing lines which may terminate in first numericalswitches. At the intersection of the line and link conductors and at theintersection of the link and trunk conductors contact sets are provided,certain predeteunined contact sets being automatr cally instantaneouslyinterconnected upon the initiation of a call to extend a calling line toan idle trunk by means of'electromagnetically actuated operating barsarranged in intersecting relation so as; to co operate to interconnectsaid preselected contact sets.

three allotting switches for preselecting links from each group andoutgoing trunks for use. The structural features are not shown in detailsince there are in the art structures which may be used in carrying Outth w a A examp of @"Sflii able switching structure is shown in Patent1,323,318 to J. N. Reynolds, issued December2, 1919. V

Inasmuch as the invention does not lie in the switch structures per sewhich is fully to advance in search of an idle link or transfer circuitto preselect the same in readiness for the next call, and shown in thedrawing, the link circuit in question is the one at the extreme right.It will of course be understood that although only two subscrib erslines A and B of one line group, and only two link circuits 4'and 5individual to that group, and only two-subscribers lines G and D ofanother group and two link circuits 80, 83 individual to that group areillustrated, to simplify the disclosure, each line group may contain ahundred subscribers lines and each link group may comprise ten linkcircuits. The number of link circuits serving a given line group dependsupon the trafiic in the line group which they serve; and the number oftrunks depends upon the traiiic in all of the groups of lines which theyserve,

It will be assumedthat the next call is initiated at substation A. Thiscauses the relay 6 individual to such line to operate. In attracting itsupper armature this relay closes acircuit to operate magnet 7 of thelink circuit 4 which was preselected by the link circuit allotter 3 whensubstation B was extended to trunk 1. This circuit is as follows:grounded upper armature of relay 6, conductor 8, armature and normalcontact of slow release relay 9, brush 10 of link circuit allotter 3,terminal 11, conductor 12, magnet 7 to battery and ground. Magnet 7 inattracting its right armature rotates av bar, the pivot pins 13, 14,whereof only. are shown, to position the multiple contact sets of theconducting strips 4, which maybe carried bythe bar, in operativerelation to multiple contact sets of the conducting strips 15, 16, etc.of lines A and B, etc, and to multiple contact sets of the conductingstrips 17, 18, etc, of trunks 1, 2, etc. Mag net 7, inattract-ing itsleft armature, closes a circuit to operate the trunk bar actuatingmagnet 19 of the trunk 2 preselected by the trunk allotter 20. This,allotter moved its brush 21 from engagement with terminal v22- connectedto the bar actuating magnet 24 of trunk l and into engagement withterminal 23 connected to bar actuating magnet 19 of trunk 2 whensubstation B was extended to trunk 1. The circuit for operating magnet24 is as follows: ground, left armature and alternate contact of magnet7, conductor 25, armature and normal contact of slow release relay 26,brush 21, terminal 23, mag

net 19 to battery and ground. Magnet 19 in attracting its right armaturefirst rotates a trunk bar, the pivot pins 27, 28 only whereof are shown,until the multiples 29, 3Q, 31 of the trunkconducting strips 18, whichmay be carried by the bar, are in operative relation to multiples 32,'34 ofthe link conducting strips 4-. Upon further attraction of theright armature of magnet 19 the trunk bar is forced to the left, movingmultiples 29, 30, 31 into engagement with multiples 32, '33, 34respectively, and also moves the remaining multiples of the trunkconducting strips 18 to a position where they will not be engaged by themultiples of a subsequently operated link bar.

Magnet 19 in attracting its left armature closes a circuit to operatethe bar actuating magnet 35 of the calling line A. This circult is asfollows: ground, left armature and alternate contact of magnet 19,conductors 36,37, 38, lower armature and alternate contact of relay 6,right winding of magnet 35 to battery and ground. Magnet 35 in attracting its right armatures cuts off the line relay (5 and inattracting its left armature first'rotates the line bar, the pivot pins40, 41 only whereof are shown, until the multiples 42, 43, 44, of lineconducting strips 15 which may be carried by the bar, are inoperativerelation to multiples 45, 46, 47 of the link conducting strips4 to which the trunk 2 is already connected. Upon further attraction ofthe armature of magnet 35 the linebar is forced to the left. movingmultiples 42, 43, 44 into engagement with multiples 45, 46, 47,respectively, and a.so moves the remaining multiples of the lineconductin strips to a position where they will not be engaged by themultiples of a subsequently operated link bar. 7 a

The incoming line A is now the outgoing trunk 2 and relay 48 newoperates in series with the substation equipment of the calling line A.The circuit is as follows: free pole of battery, lower left winding ofrepeating coil 53, relay 48, trunk conductor 49, middle strip of thetrunk conducting strips 18, trunk multiple 30, link multiple 33, middlestrip of the link conducting strips 4. link multiple 46,1ine mul tiple43, middle strip of the line conducting strips 15, line conductor 50,the telephone apparatus (not shown) at substation A, line conductor 51,upper strip of the line conducting strips 15, line multiple 42, linkmulextended to i IOU tiple 45, right strip of the link conducting strips4, link multiple 32, trunk multiple 29, upper strip of the trunkconducting strips 18, trunk conductor 52, upper left winding of therepeating coil 53, to ground.

Relay 48, in attracting its armature, closes a circuit for test relay 54of the link allotter 3 to cause it to advance and preselect an idle linkin readiness for the next call. The circuit for relay 54 is as follows:ground, armature and alternate contact of relay 48, conductor 55, lowerstrip of the trunk conducting strips 18, multiple 31 thereof, multiple34 and the left conducting strip of the link strips 4, conductor 56,brush 57, relay 54 to battery and ground. Relay 54 in attracting itsarmature closes the circuit of stepping magnet 58 of the link allotter3. The attraction of the'armature of magnet 58 prepares, through thepawl 59 and ratchet 60, for the rotation of the shaft carrying thebrushes 10 and 57 to move the said brushes over their terminal rows 61and 62 respectively upon the subsequent deenergization of magnet 58. Aslong as wiper 57 encounters test contacts of busy link circuits uponwhich ground is present, the circuit of test relay 54 will remainclosed, thus holding closed the circuit of self-interrupting magnet 58.As soon as wiper 57 is centered on a test terminal of the row 62corresponding to an idle link circuit. no ground will be presentthereon, since relay 48 thereof is inert and test relay 54 will release,opening the stepping circuit including magnet 58. release relay 9 isprovided to prevent the operation of any of the link bar operatingmagnets 7 during the operation of the allotter 3. This relay is operatedin parallel with test relay 54 from the grounds on the busy testterminals of the row 62. As soon as brush '10 leaves terminal 11 towhich. the magnet 7 is connected, the circuit of this magnet'is openedand it releases and allows the link bar carrying the conducting strips 4to return to its normal position. The set of multiple terminals 32, 33,34 engaging the set of multiple terminals 29, 30, 31, respectively,remain in contact,however, due to the flexibility of said terminals. Theother sets of terminals of the link conducting strips 4 are rotated in acounter clockwise direction to place them in a position where they willnot be engaged by terminals carried by the bars of subsequent callinglines.

Relay 48 in attracting its armature also closes a circuit for test relay63 of the trunk allotter 20 to cause it to advance and preselect an idletrunk. The circuit for relay 63 is as follows: ground, armature andalternate contact of relay 48, conductor 55, lower strip of the trunkconducting strips 18, conductor 64, terminal 92, brush 65, test relay 63to battery and ground. Relay 63in attracting itsarmature closes thecircuit of stepping magnet 66 of the trunk allotter 20. The attractionof the armature of magnet 66 prepares, through the pawl 67 and ratchet68, for the rotation of the shaft carrying the brushes 21, to move thesaid brushes over their terminal rows 69, 70, respectively, upon thesubsequent deenergization of magnet 66. As long as wiper 65 encounterstest contacts of busy trunk circuits upon which ground is present, thecircuit of test relay 63 will remain closed, thus holding closed thecircuit of self-interrupting magnet 66. As soon as wiper 65 is centeredon atest terminal of the row 70 corresponding to an idle trunk circuit,no ground will be present thereon and test relay 63 will become inert,opening the stepping circuit including magnet 66. A slow release relay26, similar to slow relay 9, is provided to prevent the operation of anyof the trunk bar operating magnets 24, 19, during the operation of thetrunk allotter 20. This slow relay is operated in parallel with testrelay 63 from the grounds on the busy test terminals of the row 70. Assoon as brush 21 leaves terminal 23 the circuit of magnet 19 is opened,but due to the operation of relay 48 a circuit was already closed formagnet 71 which magnet holds armature 72 attracted to hold the trunk barcarrying the conducting strips 18 set to maintain trunk multiples 29,30, 31 in contact with link multiples 32, 33, 34. The ground applied tothe lower conducting strip of the strips 18 is extended over multiples31, 34, the left strip of the conducting strips 4, multiples 47, 44, thelower strip of the conducting strips 15, to the left winding of the linebar operating magnet 35 whereby this magnet maintains its left armatureattracted to hold the line bar set to maintain the multiples 42, 43, 44in contact with multiples 45, 46, 47 after the circuit through the rightwinding of magnet 35 is opened by the retraction of the lower armatureof the line relay 6 when it is cut off from the line due to theoperation of magnet 35. This circuit for the left winding of magnet 35is closed before the circuit including the right winding of said magnetis opened by the release of the line relay 6. The mechanicalconstruction for accomplishing this function is not shown since sucharrangements are well known. The ground applied by relay 48 to the lowerconducting strip 18 and over the path traced to the holding winding ofmagnet 35 is extended by conductor 74 to the called multiples of line Ato cause the line to test busy at such multiples in the wellknownmanner.

The calling line A is new extended to trunk 2 and the allotters .3 and20 have preselected idle link and trunk circuits respectively inreadiness for the next call. The calling line A may now be extended inthe direction of the called line over the trunk 2 in any suitablemanner. For example, the

. theline circuit A causes the release of magnets 71 and 35. Thedeenergization of magnet 71 and consequent retraction of its rightarmature releases the trunk bar carrying the conducting strips 18 whichbar is returned to its normal position by springs (not shown).

The'rele'ase of the armature of'relay '48 also removes ground fromtheterminal 92 of row 70 of the trunk allotter 20 to indicate the idlecondition of the used trunk in the trunk allotter 20; The release of thearmature of relay 48 also removes ground from the second terminalin row62 of the link allotter 3 to indicate the idle condition of the usedlink in the link allotter. The deenergization of the line bar operatingmagnet 35 and terminals.

position by springs (notshown).

consequent retraction of its left armature releases the line'barcarrying the conducting strips 15 which bar is returned to its normalThe deenergization of the line bar operating magnet 35 causes theretraction of its right armatures, reconnecting the line relay 6 totheline A.

When the relay 48 removed ground from conductor 55 and released magnet35, the removal of this ground from the third wire 74 leading to thecalled multiples of line A causedthis line to test idle at such calledhen line A is seized as a called line, ground is placed on conductor 74completing a circuit for the left winding of magnet 35. The winding'isconstructed and. arranged to magnetize the magnet sufficiently to causeit to attract its right armatures to cutoff the associated line relay 6,but insufficiently to cause it to actuate its left armature to move thebar carrying the multiple sets of contacts on the conducting strips 15.

As previously indicated, another-group of subscribers lines of whichonly two, C and D, are shown, is indicated at the left of the drawing.Each line of this group. is similarly provided with threeconductingstrips '75 which may be carried by a bar, the pivot pins 76, 77 onlywhereof are shown. These strips are similarly provided with sets ofmultiple contacts 78, 81, for engagement with sets of multiple contacts79, 82 respectively of link conducting strips 80, 83,

provided with aline relay 84 and a line bar operating magnet 85. Thelink circuits and 83 are similarly provided with a link allotter 86 forpreselecting an idle link circuit. In the drawing the idle link circuitis shown as the first to the left, the operating magnet 87 of this linkcircuit being connect ed by'the brush 88 to the conductor 89 extendingto the upper armatures of the line relays of the subscribers lines ofthis group.

In view of the operations already described it is thought unnecessary todescribe in detail the operations involved in establishinga connectionfrom line C or D toone of the trunk circuits. The initiation of a callin line C, for example, operates its line relay 84 which energizesmagnet 87 to position multiples 79 and 90 of the preselected idle linkcircuit 80 in operative relation to multiples 78 and 91 respectively ofthe line and trunk conducting strips, so thatupon the operation ofmagnets 87 and 85 and the trunk magnet such as magnet 24, the connectionis extended to the trunk preselected by trunk allotter 20.

It will be noted that the link conductors 4, 5, 83, 80, etc., of bothline groups intersect all the trunk conductors 17, 18, etc. and

that each set of link conducting strips has a set of multiple contactsadapted to cooperate with a set of multiple contacts on each set oftrunk conducting strips, whereby through the cooperation of the line andtrunk bars any subscribers line of any group may seize any trunk; inother words, by virtue of the present invention a unitary structure isprovided in which trunks common to all the subscribers lines termi'nate, and if any trunk is idle any line in any group may seize it.

7 It is to be understood that although the incoming lines are shown anddescribed as subscribers lines, these lines may thClTlSBlVG: be incomingtrunk lines to be extended by the switching unit of this invention toone of a number of trunks 1, 2, etc., whereby the connection may beextended in the direction of the called line.

That is claimed is: V

1. In a switching system, a unitary switching apparatus comprising setsof incoming line conductors, sets of link conductors primarilyaccessible from said sets of incoming conductors, sets of outgoingconductors, means for preselecting an idle set of link conductors, meansfor preselecting an idle set of outgoing conductors, and means forconnecting any set of incoming line conduc' tors with an'idle one of anyof said sets of outgoing conductors through an idle setof linkconductors. a Y

2. In a switching system, a unitary switching apparatus comprising setsof incoming line conductors, sets of link conductorsprimarily accessiblefrom said sets of incoming line conductors, sets of outgoing trunkconductors, line bars serving said line conductors, link barsserving-said link conductors, trunk bars serving said trunk conductors,means for pr'eselecting an idle link bar and an idle trunk bar, andelectromagnetic means for actuating said bars to connect a set ofincoming line conductors with an idle one or any of said set of trunkconductors through an idle set of link conductors.

3. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, trunkcircuits, contact sets, incoming circuit bars serving said incomingcircuits, link bars individual to said links, trunk bars individual tosaid trunks, magnets for causing the joint actuation of an incomingcircuit bar, a link bar and a trunk bar, said bars cooperating with eachother to actuate predetermined contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable one or" said trunk circuits, and circuits for said magnetsclosed upon the closure of one of said incoming circuits.

4. The combination, in a switching system, of incoming line conductors,a central ofiice, a switching apparatus thereat wherein said conductorsterminate in groups, extensions of said conductors mounted on saidapparatus, a group of sets of link conductors for each incoming linegroup mounted on said apparatus intersecting the extensions of itsincoming line group and primarily accessible therefrom, a group of setsof trunk conductors intersecting theconductors of all of said linkgroups, and means for connecting a set of incoming line conductors toany set of idle link conductors of its group and to connect such set oflink conductors to any available one of said sets of trunk conductors.

5. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a plurality of switching bars cooperatingwith each other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit.

6. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a V plurality of intersecting switching barsact ing jointly and cooperating with each other for actuating saidcontact sets to connect any incommg circuit with a link circuit and 1 toconnect such link circuit to any available outgoing circuit.

7. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, a plurality of switching bars cooperating witheach other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit, and means for restoring one of said barswithout releasing the established connection.

8. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, a plurality of switching bars cooperating witheach other and actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to an idleone of any of said outgoing circuits, and means for preselecting thelink circuits and outgoing circuits.

9. The combination, in a switching system, of line circuits, linkcircuits primarily accessible from said line circuit-s, trunk circuits,contact sets, line bars serving said lines, link bars serving saidlinks, trunk bars serving said trunks, and means for causing the jointoperation of a line bar, a link bar and a trunk bar, said barscooperating with each other for actuating said contact sets to connect aline to a link and to connect such link to any available trunk.

10. The combination, in a switching system, of incoming circuits dividedinto subgroups, a group of link circuits individual to each sub-group ofincoming circuits and primarily accessible from the subgroup of incomingcircuits to which it is individual, outgoing circuits common to all linkcircuits, a plurality of switching bars cooperating with each other, andmeans for operating the same for connecting an incoming circuit to alink, and for connecting said link to any available one of said outgoingcircuits.

11. In a switching system, a unitary switching apparatus comprising setsof incoming line conductors, sets of link conductors primarilyaccessible from said sets of incoming line conductors, sets of outgoingconductors less in number than said sets of incoming conductors, meansfor preselecting an idle set of link conductors, means for preselectingan idle set of outgoing conductors, and means for connecting any set ofincoming line conductors with an idle one of any of said sets ofoutgoing conductors through an idle set of link conductors.

12. In a switching system in which a unitary switching apparatus isemployed for establishing connections between incoming circuits andoutgoing circuits through the intermediary of link circuits, the methodof establishing connections which consists in preselecting an idleoutgoing circuit, preselecting an idle link circuit, making each linkcircuit primarily accessible from each incoming circuit, c0unecting 'anypreselected outgoing circuit to any. preselected link circuit, and thenconnecting such preselected link-circuit to an incoming circuit.

Inna switching system in which a unitary. switching apparatus isemployed for establishing connections between incoming circuits of aplurality of groups and outgoing circuits of a group common theretothrough the intermediary of link circuits of groupsindividualrespectively to the groups of incoming circuits, the method ofestablishing connections Which consists in prese lecting an idleoutgoing'circuit,preselecting an idle link circuit in each of the groupsof link circuits, making each link circuit of a group primarilyaccessible from each in coming circuit of the; group to which that groupof link circuits is individual, connecting any incomingcircuit With anypreselected link circuit of the group accessible therefrom, and thenconnecting such link circuit With the preselected outgoing circuit. y InWitness whereof, I hereunto subscribe my name this 23rd day of NovemberA. D.,

JAMES L. LMCQU RRIE.

DISOLAEMERB 1,543,937.James L. McQmmw'e, New York, N. Y. AUTOMATICTELEPHONE-EX- CHANGE SYSTEM. Patent dated June 30, 1925. Disclaimerfiled October 22, 1926, by the patentee, assignee, W eszfem mamaCompany, Incorporated, consenting. 4 Hereby enters this disclaimer tothe said claims of said Letters Patent which are in the following words,to wit:

5. The combination, in a switching system, of incon'iing circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a plurality of switching bars cooperatingwith each other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit.

6. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a plurality of intersecting switching barsacting jointly and cooperating with each other for actuating saidcontact sets to connect any incoming circuit with a link circuit and toconnect such link circuit to any available outgoing circuit.

7. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, a plurality of switching bars cooperating witheach other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit, and means for restoring one of said barswithout releasing the established connection.

[Oficc'al Gazette Nooember .76, 1926.]

DISCLAIMER 1,543,937.Ja71ws Z. McQuwrfic, New York, N. Y. AU'roMA'rIoTELEPHONE-EX- CHANGE SYSTEM. Patent dated June 30, 1925. Disclaimerfiled April 4, 1928, by the assignee, W estem Electric Oompany,Incorporated.

Hereby enters this disclaimer to that part of the claims in saidspecification which are in the following words to wit:

5. The combination, in a switching system, of incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a plurality of switching bars cooperatingWith each other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit.

6. The combination, in a switching system, of incon'iing circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, and a plurality of intersectin switching barsacting jointly and cooperating with each other for actuating saidcontact sets to connect any incoming circuit with a link circuit and. toconnect such link circuit to any available outgoing circuit.

7, The combination, in a switching system, o1 incoming circuits, linkcircuits primarily accessible from said incoming circuits, outgoingcircuits, contact sets, a plurality of switching bars cooperating witheach other for actuating said contact sets to connect an incomingcircuit to a link circuit and to connect such link circuit to anyavailable outgoing circuit, and means for restoring one of said barswithout releasing the established connection.

[Ofiicz'al Gazette May 1, 1928.]

